This invention relates to olefin isomerization. In one of its more specific aspects, this invention relates to selective isomerization of olefins.
More particularly, the present invention relates to a process for the preparation of useful hydrocarbons by catalytic conversion of n-butylenes.
MTBE (methyl tertiary butyl ether) is an effective octane booster. It is made from isobutylene and methanol. The present sources of isobutylene for MTBE production are mainly from by products of steam, catalytic cracker, and propylene oxide production. However, these supplies are limited. Other possible sources are by isomerization of n-butenes taken from steam or catalytic crackers and by dehydrogenation of isobutane taken from field butanes or produced by isomerization of n-butane.
Olefin isomerization processes can be directed towards either skeletal isomerization or double bond isomerization. Skeletal isomerization is concerned with reorientation of the molecular structure in respect to the formation or elimination of side chains. Double bond isomerization is concerned with relocation of the double bond between carbon atoms while maintaining the backbone of the carbon structure. Most isomerization processes give rise only to double bond isomerization.
The minimum Bronsted Acid strengths (and equivalents in H.sub.2 SO.sub.4) required for various acid-catalyzed conversions of hydrocarbons are indicated in the table below.